/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.util.concurrent;

import io.netty.util.internal.PromiseNotificationUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import static io.netty.util.internal.ObjectUtil.checkNotNull;

/**
 * {@link GenericFutureListener} implementation which takes other {@link Promise}s and notifies them
 * on completion.
 *
 * @param <V> the type of value returned by the future
 * @param <F> the type of future
 */
public class PromiseNotifier<V, F extends Future<V>> implements GenericFutureListener<F> {

  private static final InternalLogger logger = InternalLoggerFactory
      .getInstance(PromiseNotifier.class);
  private final Promise<? super V>[] promises;
  private final boolean logNotifyFailure;

  /**
   * Create a new instance.
   *
   * @param promises the {@link Promise}s to notify once this {@link GenericFutureListener} is
   * notified.
   */
  @SafeVarargs
  public PromiseNotifier(Promise<? super V>... promises) {
    this(true, promises);
  }

  /**
   * Create a new instance.
   *
   * @param logNotifyFailure {@code true} if logging should be done in case notification fails.
   * @param promises the {@link Promise}s to notify once this {@link GenericFutureListener} is
   * notified.
   */
  @SafeVarargs
  public PromiseNotifier(boolean logNotifyFailure, Promise<? super V>... promises) {
    checkNotNull(promises, "promises");
    for (Promise<? super V> promise : promises) {
      if (promise == null) {
        throw new IllegalArgumentException("promises contains null Promise");
      }
    }
    this.promises = promises.clone();
    this.logNotifyFailure = logNotifyFailure;
  }

  @Override
  public void operationComplete(F future) throws Exception {
    InternalLogger internalLogger = logNotifyFailure ? logger : null;
    if (future.isSuccess()) {
      V result = future.get();
      for (Promise<? super V> p : promises) {
        PromiseNotificationUtil.trySuccess(p, result, internalLogger);
      }
    } else if (future.isCancelled()) {
      for (Promise<? super V> p : promises) {
        PromiseNotificationUtil.tryCancel(p, internalLogger);
      }
    } else {
      Throwable cause = future.cause();
      for (Promise<? super V> p : promises) {
        PromiseNotificationUtil.tryFailure(p, cause, internalLogger);
      }
    }
  }
}
